Photosynthesis is the basis of primary productivity on the planet. Crop breeding has sustained steady improvements in yield to keep pace with population growth increases. Yet these advances have not resulted from improving the photosynthetic process per se but rather of altering the way carbon is partitioned within the plant. Mounting evidence suggests that the rate at which crop yields can be boosted by traditional plant breeding approaches is wavering, and they may reach a “yield ceiling” in the foreseeable future. Further increases in yield will likely depend on the targeted manipulation of plant metabolism. Improving photosynthesis poses one such route, with simulations indicating it could have a significant transformative influence on enhancing crop productivity. Here, we summarize recent advances of alternative approaches for the manipulation and enhancement of photosynthesis and their possible application for crop improvement.

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The muskmelon plants allow several ways to manipulate sources/ drains ratio. The objective of this work was to evaluate characteristics of the productivity and quality of Cantaloupe melon fruits due to the temporary use of row cover and the number of fruits per plant. The experiment was carried out from August to December 2014, at Universidade Federal de Campina Grande (UFCG), Paraiba State, Brazil. The experimental design was randomized blocks with treatments allocated in split plots 5x3, with four replicates. The authors reported permanence time of the row cover at different times in the plot [20, 24, 28, 32, and 36 days after transplanting (DAT)] and, in the subplots, the number of fruits per plant (plants with one fruit, plants with two fruits and fruit-free setting plants). The authors evaluated traits of production and quality of fruits. The permanence time of row cover and number of fruits per plant promoted changes in the productivity and quality of the muskmelon fruits. The permanence of the row cover from 20 to 36 DAT provided reduction in the total soluble solids. The average fruit mass and fruit yield reached the maximum value with the permanence of the row cover up to 26.6 and 25.1 DAT, respectively. Plants with one and two fruits presented higher average fruit mass, but with lower productivity compared to the plant with fruit-free setting.

Squashes and pumpkins are known and grown worldwide, including the Tetsukabuto type, a hybrid of Japanese origin. On this work, we evaluated yield and quality of parthenocarpic fruits of hybrid Tetsukabuto developed with the use of 2,4-D doses, in the climatic conditions of the Brazilian semiarid, in the city of Pombal, state of Paraíba, Brazil. The experiment was carried out from February to May 2013, in complete blocks at random and five replications. Treatments corresponded to five 2,4-D doses (0, 90, 180, 270, and 360 mg/L) applied to female flowers, and a control treatment, where fruits developed out of insect pollinated flowers. We evaluated number of flowers per plant, duration of flowering, number of fruits per plant (used to estimate number of fruits per hectare), fruit set index, fruit mass and transversal and longitudinal diameters, pulp thickness and content of soluble solids, total fruit production and yield. Number of fruits per plant and fruit mass increased 269.5 and 15.4%, respectively, with 212.1 mg/L and 360.0 mg/L of 2,4-D, when compared to the control treatment. Increasing the 2,4-D dose from 0.0 to 241.4 mg/L resulted in 38.2% rise in plant production. Correlations were significant only for number of flowers x number of fruits per plant (NF) and NF x yield, with coefficients of 87.5 and 82.7%, respectively. These results indicate that fruit induction using 2,4-D resulted in higher fruit set, independent of the 2,4-D dose applied.

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Este artigo analisa a prática da pistolagem nos conflitos terra no sul e no sudeste do Pará, na Amazônia Oriental, tomando como caso o envolvimento de Sebastião Pereira Dias, o Sebastião da Teresona, nos assassinatos de trabalhadores rurais. Este homem coordenava um grupo com mais de trinta membros que trabalhava para proprietários de terra. Mas a atuação de pistoleiros nas disputas por terra nessa parte do território amazônico provavelmente teria sido pouco eficiente se não tivesse encontrado suporte nas ações de muitos agentes do Estado.Palavras-chave: Conflitos de terra; violência; pistolagem.

A partir de análises de fontes orais, escritas e audiovisuais, este texto procura analisar a participação da Igreja Católica nos conflitos pela posse da terra, em São Geraldo do Araguaia, no sudeste do Pará, nas décadas de 70 e 80, do século XX. Nessas duas décadas, devido a atuação de agentes de pastorais, padres e freiras cada vez mais próximos da realidade das comunidades rurais, sobretudo aquelas formadas por posseiros, a hierarquia da Igreja Católica ao se posicionar do lado dos trabalhadores rurais e de seu clero, entrou em choque não só com os grandes proprietários e empresas rurais, mas com o Estado que, na época, defendia o desenvolvimento da Amazônia pautado na grande propriedade da terra, principalmente para criação de gado bovino. Foram nessas circunstâncias que os membros da Igreja Católica, principalmente devido a sua reação à violência dos latifundiários e do regime totalitário da época, passaram a viver e trabalhar mais intensamente junto aos trabalhadores rurais e a falar em políticas de libertação.

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